Hi Buehgemeiste
Have you used a plastic enclosure?
How did you connect the 3 pin connector for the input? On ebay ther are special cables "2.0CH Audio Input Connector Cable" (i have bidden, but I don't want to pay EUR 5 for that cable, it's not even shielded). I have ordered the tda7498 today and I'm awaiting the delivery (I'm also waiting for the tda7297 board, which was € 3,23). Has anybody used the tda7498 with 12V? According to the data sheet, it would work and deliver about 12W, which would be sufficient to me with minimum distortions. I wonder weather or not the cooler is sufficient for 100W (passiv).

omg, i´m really a noob, so i hope some of the more experienced guys will support us.

yes, i have tried both plastic and metal enclosures.
both work well for me.

the 3 pin connector is a special type of jst-connector.
jst + two letters, but i do not remind which atm.
for testing and fast switching between hardware i use dupont wire.
you can remove the connector carefully and wire the rca-connectors (or whatever you use) directly to the board.
inside one enclosure i gave to a friend i used a crimped connector like this one Housing Connector 2.54mm 3 Pins
but i had to cut away some of the plastic surrounding the pins on the amp, so the connector fits in.
if you are willing to modify the plastic you can use pretty much any connector for 2.54mm pitch.

I will use a metall case and I will use short cables to my subwoofer, because the cables and the speaker influence the characteristics of the class d amplifier (by the way I bought the US $12.86 tda7498 from aliexpress, tzt trading including free transport to Switzerland). I read that class d especially tripath cause high frequency emi, hopefully I needn't add an elektor HF Filter.

I have one of these on the way too (paid $12.67 during the 11.11 sale on Aliexpress) along with this PSU which I got for $18.65 including shipping. Will be fun to see what such cheap parts can do with my Q Acoustics 2050i speakers.
Btw. the impedance of the speakers is rated 6Ω nominal (4Ω minimum). Does that call for any mods?

edit:
R1 and C1 are smd parts beneath the heatsink (long traces between the chip and the L's).
The 220n (blue) are 22K63 and look very cheap.
The 33n seems to be a film resistor.
R2 is a 5W rated cement resistor.